Less is more for reef-building corals

Inflexibility of coral host leads to higher resistance to environmental stresses

2012-08-29

(Press-News.org) Researchers at the University of Hawaii – Manoa (UHM) School of Ocean and Earth Science and Technology (SOEST) made a discovery that challenges a major theory in the field of coral reef ecology. The general assumption has been that the more flexible corals are, regarding which species of single celled algae (Symbiodinium) they host in coral tissues, the greater ability corals will have to survive environmental stress. In their paper published August 29, 2012, however, scientists at the Hawaii Institute of Marine Biology (HIMB) at SOEST and colleagues documented that the more flexible corals are, the more sensitive to environment disturbances they are.

"This is exactly the opposite of what we expected," said Hollie Putnam, PhD candidate at UHM and lead author of the study. This finding was surprising, as it is thought corals exploit the ability to host a variety of Symbiodinium to adapt to climate change. "Our findings suggest more is not always better," she continued.

"The relationship of coral species to their algal symbionts is fundamental to their biology," says David Garrison, program director in the National Science Foundation (NSF)'s Division of Ocean Sciences, which funded the research. "This study gives us a new understanding of how corals are likely to respond to the stresses of environmental change."

Reef corals are the sum of an animal (host), and single celled algae that live inside the corals' tissues (also called 'endosymbionts'). This is a mutually beneficial arrangement – the coral provide protection and keep the algae in shallow, sunlit seas; and the algae produce large amounts of energy through photosynthesis, which coral use to survive and build their skeletons. The stability of this symbiosis is critical to the survival of corals and if they lose their endosymbionts they bleach and often die. Corals can host different types of endosymbionts, which affects their response to stress.

Putnam and other scientists from Dr. Ruth Gates' laboratory at HIMB took tiny tissue samples from 34 species of coral in Moorea, French Polynesia. By analyzing the DNA from the endosymbionts in these samples, they were able identify the types of Symbiodinium. This revealed that some corals host a single Symbiodinium type that is the same in all individuals of that coral species, and that others host many types that vary among individuals within a coral species.

"The corals we sampled spanned a range of environmental sensitivities from resistant to susceptible, and we were able to link, for the first time, patterns in environmental performance of corals to the number and variety of symbionts they host," reported Putnam. These patterns show that corals hosting diverse Symbiodinium communities, those that are flexible with respect to endosymbionts (termed 'generalists'), are environmentally sensitive. In contrast, environmentally resistant corals were those that associate with one or few specific types of Symbiodinium (termed 'specifists').

"Coral reefs are economically and ecologically important, providing a home for a high diversity of organisms necessary for food supplies, recreation, and tourism in many countries. The better we understand how corals respond to stress, the more capable we will be to forecast and manage future reefs communities," said senior author Professor Ruth Gates. Coral reefs can undergo mass mortality due to high temperatures, and ocean acidification is threatening the capacity for skeletal growth. These global stressors are superimposed on the local threats of pollution, coastal development and overfishing, together threatening the persistence of corals as a functional ecosystem in the future.

In the future, the Gates Lab will examine what causes the differences in success between corals that are flexible and inflexible in their Symbiodinium associations and compare the symbiotic flexibility in corals and reefs across much larger areas – in locations such as Hawaii, Moorea, Taiwan and American Samoa. This further understanding will allow better predictions of the future of reefs under further ocean warming and acidification.

INFORMATION:

The research was conducted at NSF's Moorea Coral Reef Long-Term Ecological Research (LTER) site, one of 26 such NSF sites around the globe in ecosystems from coral reefs to freshwater lakes, and from forests to grasslands. To read the Award Abstract for this work, visit http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=0417412

Proceedings of the Royal Society B: Endosymbiotic flexibility associates with environmental sensitivity in scleractinian corals; Hollie M Putnam, Michael Stat, Xavier Pochon, and Ruth D Gates

For more information about the research activities from the Ruth Gates Lab, visit http://www2.hawaii.edu/~rgates/Gates_Lab_Website/Gates_Lab.html

To learn more about the National Science Foundation-funded Moorea Coral Reef Long Term Ecological Research program, please visit http://mcr.lternet.edu/

[Attachments] See images for this press release:

ELSE PRESS RELEASES FROM THIS DATE:

Small family size increases the wealth of descendants but reduces evolutionary success

2012-08-29

Scientists have taken a step closer to solving one of life's mysteries – why family size generally falls as societies become richer. Evolutionary biologists have long puzzled over this because natural selection is expected to have selected for organisms that try to maximise their reproduction. But in industrialised societies around the world, increasing wealth coincides with people deliberately limiting their family size – the so-called 'demographic transition'. In a study published in Proceedings of the Royal Society B: Biological Sciences, researchers from the London ...

Kepler discovers planetary system orbiting 2 suns

2012-08-29

Astronomers at the International Astronomical Union meeting announced the discovery of the first transiting circumbinary multi-planet system: two planets orbiting around a pair of stars. The discovery shows that planetary systems can form and survive even in the chaotic environment around a binary star. And such planets can exist in the habitable zone of their stars. "Each planet transits over the primary star, giving unambiguous evidence that the planets are real," said Jerome Orosz, Associate Professor of Astronomy at San Diego State University and lead author of the ...

NASA, Texas astronomers find first multi-planet system around a binary star

2012-08-29

Fort Davis, Texas — NASA's Kepler mission has found the first multi-planet solar system orbiting a binary star, characterized in large part by University of Texas at Austin astronomers using two telescopes at the university's McDonald Observatory in West Texas. The finding, which proves that whole planetary systems can form in a disk around a binary star, is published in the August 28 issue of the journal Science. "It's Tatooine, right?" said McDonald Observatory astronomer Michael Endl. "But this was not shown in Star Wars," he said, referring to the periodic changes ...

Why are there so many species of beetles and so few crocodiles?

2012-08-29

There are more than 400,000 species of beetles and only two species of the tuatara, a reptile cousin of snakes and lizards that lives in New Zealand. Crocodiles and alligators, while nearly 250 million years old, have diversified into only 23 species. Why evolution has produced "winners" — including mammals and many species of birds and fish — and "losers" is a major question in evolutionary biology. Scientists have often posited that because some animal and plant lineages are much older than others, they have had more time to produce new species (the dearth of crocodiles ...

Space-warping white dwarfs produce gravitational waves

2012-08-29

Gravitational waves, much like the recently discovered Higgs boson, are notoriously difficult to observe. Scientists first detected these ripples in the fabric of space-time indirectly, using radio signals from a pulsar-neutron star binary system. The find, which required exquisitely accurate timing of the radio signals, garnered its discoverers a Nobel Prize. Now a team of astronomers has detected the same effect at optical wavelengths, in light from a pair of eclipsing white dwarf stars. "This result marks one of the cleanest and strongest detections of the effect of ...

NASA watching Isaac's approach to US Gulf Coast

2012-08-29

VIDEO: An animation of satellite observations from August 26-28, 2012 shows Tropical Storm Isaac moving past the Florida Keys and into the Gulf of Mexico, nearing landfall in the U.S. Gulf... Click here for more information. NASA satellites have been providing valuable data to forecasters at the National Hurricane Center watching the development and progression of powerful Tropical Storm Isaac as it heads for landfall. The Moderate Resolution Imaging Spectroradiometer ...

Having to make quick decisions helps witnesses identify the bad guy in a lineup

2012-08-29

Eyewitness identification evidence is often persuasive in the courtroom and yet current eyewitness identification tests often fail to pick the culprit. Even worse, these tests sometimes result in wrongfully accusing innocent suspects. Now psychological scientists are proposing a radical alternative to the traditional police lineup that focuses on eyewitnesses' confidence judgments. In a new article forthcoming in Psychological Science, a journal of the Association for Psychological Science, Neil Brewer of Flinders University and colleagues report a new type of lineup ...

Study finds gene that predicts happiness in women

2012-08-29

Tampa, FL (Aug. 28, 2012) -- A new study has found a gene that appears to make women happy, but it doesn't work for men. The finding may help explain why women are often happier than men, the research team said. Scientists at the University of South Florida (USF), the National Institutes of Health (NIH), Columbia University and the New York State Psychiatric Institute reported that the low activity form of the gene monoamine oxidase A (MAOA) is associated with higher self-reported happiness in women. No such association was found in men. The findings appear online ...

Can branding improve school lunches?

2012-08-29

A popular marketing ploy with junk foods and other indulgent table fare can be an equally effective tool for promoting healthier eating in school cafeterias. "Nutritionists and school lunch planners can turn the tables on children's poor eating habits by adopting the same 'branding' tactic used by junk food marketers," said Brian Wansink, an expert on the subtle cues that affect people's eating habits and professor of marketing at the Dyson School of Applied Economics and Management at Cornell University. Food marketers have associated particular foods with mascots, ...

The beat goes in the brain

2012-08-29

URBANA, Ill. — Like a melody that keeps playing in your head even after the music stops, researchers at the University of Illinois's Beckman Institute have shown that the beat goes on when it comes to the human visual system. In an experiment designed to test their theory about a brain mechanism involved in visual processing, the researchers used periodic visual stimuli and electroencephalogram (EEG) recordings and found, one, that they could precisely time the brain's natural oscillations to future repetitions of the event, and, two, that the effect occurred even after ...

Construction of a localized immune niche via supramolecular hydrogel vaccine to elicit durable and enhanced immunity against infectious diseases

Deep learning-based discovery of tetrahydrocarbazoles as broad-spectrum antitumor agents and click-activated strategy for targeted cancer therapy

DHL-11, a novel prieurianin-type limonoid isolated from Munronia henryi, targeting IMPDH2 to inhibit triple-negative breast cancer

Discovery of SARS-CoV-2 PLpro inhibitors and RIPK1 inhibitors with synergistic antiviral efficacy in a mouse COVID-19 model

Neg-entropy is the true drug target for chronic diseases

Oxygen-boosted dual-section microneedle patch for enhanced drug penetration and improved photodynamic and anti-inflammatory therapy in psoriasis

Around the world, children’s cooperative behaviors and norms converge toward community-specific norms in middle childhood, Boston College researchers report

Less is more for reef-building corals

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: